Measurement of $e^{+}{e}^{-}\to \eta J\mathrm{/}\psi$ Cross Section from $\sqrt{s}=$ 3.808 GeV to 4.951 GeV

Using data samples with an integrated luminosity of 22.42 fb${}^{-1}$ collected by the BESIII detector operating at the BEPCII storage ring, we measure the cross sections of the $e^{+}{e}^{-}\to \text{etaJ}\mathrm{/}\psi$ process at center-of-mass energies from 3.808 to 4.951 GeV. Three structures are observed in the line shape of the measured cross sections. A maximum-likelihood fit with $\psi (4040)$, two additional resonances, and a non-resonant component is performed. The mass and width of the first additional state are $(4219.7\pm 2.5\pm 4.5)\mathrm{M}\mathrm{e}\mathrm{V}\mathrm{/}{\mathrm{c}}^2$ and $(80.7\pm 4.4\pm 1.4)\mathrm{M}\mathrm{e}\mathrm{V}$, respectively, consistent with the $\psi (4230)$. For the second state, the mass and width are $(4386\pm 13\pm 17)\mathrm{M}\mathrm{e}\mathrm{V}\mathrm{/}{\mathrm{c}}^2$ and $(177\pm 32\pm 13)\mathrm{M}\mathrm{e}\mathrm{V}$, respectively, consistent with the $\psi (4360)$. The first uncertainties are statistical and the second ones are systematic. The statistical significance of $\psi (4040)$ is $8.0\sigma$ and those for $\psi (4230)$ and $\psi (4360)$ are more than $10.0\sigma$.